Hey phunk....
I like funk!
Anyway, Wavelab is what I use for CD mastering. No, not just me making little CDR's for clients to listen to, the real thing. It authors in Redbook. It allow one to place pause in between songs. It allows crossfades. The deal with levels though is the job of processing the file first. But, you can combine the two files, then insert a track marker where you want the next track to start and when you author it, the track marker is preserved, etc....
Truely a wonderful mastering software for PC in the lower end market. For around $300, I have seen nothing that really is as straight forward for mastering purposes.
toad_uk, be aware that changing levels between songs would require that you dither the file that has had it's volume changed. Any DSP function causes quantinization errors and the purpose of dithering is to "cover" these low level distortions by placing a "noise" at around the bottom of the dynamic range to "mask" the distortion. There are many ways that this can be done, and they all sound a little different.
The reason I am pointing this out is because if you were applying DSP, like compression and/or eq to a stereo .wav file, then saved it, then opened it in another program and applied more dsp, if the first DSP process applied dithering, then the second DSP process applied dithering, you would be applying dithering twice to the .wav file. This is not a good thing. Dithering should be the very last process applied to any .wav file (or aiff) before it is burned to disk. Once dithering is applied, you cannot apply ANY other DSP to it without creating more quantinization errors.
Anyway. This all really comes down to how you go about the mastering process. You best route it to:
1- Apply any compression, volume changes, effects, eq that you want.
2- Apply editing, fade outs, fade ins, etc....
3 - Apply any sample rate conversions you may need. Obviously, if you are working with files that are higher then 44.1KHz sampling rate, you will need to convert it to 44.1 before you can burn it to disk.
4 - Apply dithering to the file. Failing to do so will cause a process known as Truncate, which is where the extended bit depth of the file, a result of DSP being applied, is just lopped off when you save the file. DSP actually makes the bit depth longer then the file bit depth is, and this is what causes the quantinization errors that sound like distortion on your D/A converters. Actually, I didn't explain that very well, but trust me, dithering should be applied lastly before burning the file....
5 - Author the disk.
I am not sure if Jam applies any dithering to the file when it changes it's volume. Changing volume is of course a DSP function and will create the longer bit depth. So, if it doesn't apply dithering, then your audio will of course suffer.
There are so many implications to consider when mastering. Applying DSP muddies the waters. Dithering is yet another ingredient in the soup of audio! A careful engineer steers clear of doing any unneccesary DSP. So, think through your mastering process. But mainly, once you have applied dithering to a file, do not apply it again. The sound of that is aweful.
Good luck.
Ed